A semiconductor circuit configured of a transistor, a storage device and the like which are formed on a semiconductor chip is connected with an electric circuit or the like outside a semiconductor device by use of a contact terminal on the front surface of the semiconductor chip. Examples of the contact terminal include a solder bump. Generally, the solder bump is formed by depositing a solder layer on a bump pad, provided on the semiconductor chip, by means of plating. At this time, it is of necessity to connect the bump pad and the solder bump in an electrically favorable manner, and the electric connection therebetween has been ensured by managing a manufacturing process for the semiconductor device. Moreover, also in a semiconductor chip having a plurality of solder bumps and a semiconductor device used for a multi-chip module formed by mutually connecting a plurality of semiconductor chips, when any of electric connections between the plurality of bump pads and solder bumps has a connection failure, the whole is judged as a failure, and hence it is of necessity to ensure electric connections between all the bump pads and solder bumps.
However, even when the manufacturing process is strictly managed, it is difficult to avoid occurrence of the connection failure that occurs with a constant probability in the process of mass-producing products.
For this reason, it is considered that the electric connection between the bump pad and the solder bump is checked by performing a visual inspection on the semiconductor chip. However, even when the solder layer is properly formed on the bump pad from a visual standpoint, they may be electrically disconnected, and it is thus difficult to ensure the electric connection by the visual inspection. Moreover, when the number of solder bumps is large, e.g., several hundred, inspection cost increases, thereby making it difficult to virtually perform the visual inspection on all the solder bumps.
It is also considered that the electric connection between the bump pad and the solder bump is checked by pressing a metal probe against the solder bump for electric connection, and activating the semiconductor circuit formed on the solder chip, to inspect an operating state of the circuit. However, pressing the probe against all the solder bumps to perform the electric inspection causes an increase in inspection cost when the number of solder bumps is large or a multi-chip module is to be inspected, thereby making it difficult to virtually carry out such an inspection. Moreover, a probe mark is left on the solder bump, which can be a new cause of failure.